Having re-read the thread, I think that perhaps you're trying to do something that might seem sensible, but, actually isn't.

Despite seeming scientific and technical, tightening bolts with a torque wrench is actually a *really* poor way of tensioning a fastener, but, it is fast and simple - that's why it's so common.

When you install a fastener, what you are really trying to achieve is to apply a tensile force in the bolt, which forces the two parts of the joint together in compression. The torque you apply to the bolt is really an intermediate quantity - the bolt would work fine without any torque at all.

Indeed, some high performance bolts [think critical applications like nuclear pressure vessel lids] are tensioned by hydraulically jacking the stud away from the joint, and then running the nut down until it is snug, and then releasing the hydraulic pressure. The result is a very accurately pre-tensioned fastener, with no, or negligible torque in the bolt.

Applying torque to a fastener is an indirect way of stretching the bolt to gain this tensile force. The friction under the bolt head, and in the threads are responsible for making the relationship between applied torque and bolt tension complex and poorly repeatable. I've done tests with strain gauged bolts [M16 bolts on a rail vehicle bogie, using a freshly calibrated wrench, and highly skilled technicians] all installed to the same torque - the amount of scatter in the resulting bolt tension was frightening!

One way to avoid the inherent inaccuracy of using a torque wrench (which incidentally is not saying that the torque wrenches cannot measure torque accurately, but is saying that even with precisely measured torque, the pre-tension of the bolts is not well controlled] to gauge bolt pre-tension is to turn the bolt through a known angle. In this way, as the pitch of the thread is known, the stressed area of the bolt is known and well controlled, and the stiffness of the joint and gasket is consistent, the resulting pre-tension is also more accurately known than if a torque wrench were used.

The first 2 stages of cylinder head bolt installation are designed to make sure that the head is snugged down, and that the gasket is flattened - effectively these steps ensure that you start the serious business of tensioning the head bolts form a consistent point.

In short, angle tightening is *way* more accurate than using a torque value, and there's no sensible read across between the two methods.

Another blunt way of saying this is that if a fastener has just a torque value, then;

a) the joint is not very well optimised
b) the large margin in the joint stressing allows a wide range of bolt pre-tensions to function in an acceptable way
c) more critical joints have something better than just a torque value [wheel bolts for example can suffer all sorts of abuse by poorly skilled tyre fitters, and yet there's no great problem with wheel security on cars - trucks on the other hand should probably have a better wheel installation procedure! (do you have the same problems with truck wheel security in the US that we have in Europe?)

Apologies for both the lenght of the post, and the number of bracketed digressions - it's quite a knotty subject!